1 / 23

ATOMS_ppt

Discussion about Atoms and Molecules

GALANG2
Download Presentation

ATOMS_ppt

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The Particle Nature of Matter Atoms and Molecules

  2. Leucippus

  3. Democritus

  4. John Dalton

  5. What does these tiny particles called?

  6. ATOM

  7. What is an atom?

  8. Almost 2,500 years ago Leucippus Leucippus and his disciple, Democritus believed that: Nature consisted of two things “atoms and the void (vacuum) that surround them”. Democritus

  9. Any piece of matter can be divided and subdivided into very small particles but this process ended at some point when a piece is reached that could not be further divided. He called this particle, atomos, a Greek word which means indivisible particle. Democritus

  10. A little over two centuries ago All matter is made of very small particles called atoms. John Dalton

  11. An atom is the smallest particle of an element that has all the properties of the element. Today, we know that although atoms are very small, they are not indivisible as Democritus thought. John Dalton

  12. What is a Molecule?

  13. A molecule is a particle consisting of two or more atoms combined together in a specific arrangement. It is an electrically neutral particle. It is the smallest particle of an element or compound that can exist independently.

  14. For example: (1) A molecule of water consists of an oxygen atom combined with two hydrogen atoms. (2) Oxygen in the air consist of oxygen molecules which are made up of two oxygen atoms.

  15. Atoms are too small to observe. These particles cannot be seen under the high-powered light microscopes used in school laboratories. The size of an atom is measured in angstroms. One angstrom is a unit of length equal to one ten millionth of a millimetre.

  16. The best light microscope can magnify an image only about 1,500 times. Electron microscopes create a highly magnified image of up to 1 million times. The scanning tunelling microscope (STM) allows scientists to view and scan the surface of very small particles like atoms.

  17. The STM can magnify an image 10 million times. The STM creates a profile of the surface of an atom and then a computer-generated model or contour map is produced. So, only a model of the surface of an atom is generated by a computer when a scanning tunnelling miscroscope is used.

  18. Scanning Tunneling Microscope

  19. Sample image under STM

  20. Pointillism A good analogy to consider related to matter being composed of tiny particles is the pointillist style of painting. The images in a pointillist painting appear continous but if one looks closely, the images are actually made of small dots. Matter is similarly assembled, with atoms of different elements combining in various ways to give a tremendous variety of substances.

  21. Image of pointillist painting

  22. Image of pointillist painting

  23. 1. What is the three phases of matter? 2. Give atleast three example for each phases of matter. Also please bring the following tomorrow: 2 cups tap water 1 piece, 30 ml plastic syringe (without needle) 1 piece, wide-mouthed transparent bottle (200 or 250 ml capacity) 1 piece, narrow-mouthed transparent bottle (100 ml capacity) 1 plastic or glass dinner plate ½ cup rock salt (not iodized salt) or ½ cup sand Food coloring (blue, green, or red) Assignment

More Related